Apparatus and methods for detecting wet and icy conditions
First Claim
1. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
- a block of electrically insulative material adapted to be embedded in the pathway and having a top surface exposed to precipitation; and
sensor means embedded in said block for sensing a physical property of the precipitation to produce a sensor output which is also influenced by a depth of the precipitation, wherein part of the top surface of the block has a well that is generally curved in outline above said sensor means for gathering precipitation for said sensor means, thereby diminishing the influence of precipitation depth on said sensor means.
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Accused Products
Abstract
Apparatus that detects the presence and condition of precipitation on the surface of a pathway. The apparatus has a block of electrically insulative material adapted to be embedded in the pathway with a top surface exposed to precipitation. A sensor is embedded in the block for sensing a physical property of the precipitation to produce a sensor output which is also influenced by a depth of the precipitation. Part of the top surface of the block has a well that is generally curved in outline above the sensor for gathering precipitation for the sensor. Advantageously, the influence of precipitation depth on the sensor is diminished. Other apparatus and methods are also disclosed.
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Citations
45 Claims
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1. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
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a block of electrically insulative material adapted to be embedded in the pathway and having a top surface exposed to precipitation; and sensor means embedded in said block for sensing a physical property of the precipitation to produce a sensor output which is also influenced by a depth of the precipitation, wherein part of the top surface of the block has a well that is generally curved in outline above said sensor means for gathering precipitation for said sensor means, thereby diminishing the influence of precipitation depth on said sensor means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
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a block of electrically insulative material having a top surface and adapted to be embedded in the pathway with the top surface of the block exposed to precipitation; and sensor means for sensing a quantity related to electrical conductivity of the precipitation to produce a sensor output which is also influenced by the depth of the precipitation, wherein part of the top surface of the block is provided with a well for gathering precipitation around said sensor means, thereby diminishing the influence of depth of precipitation on said sensor means, said sensor means including a pair of conductors having portions thereof exposed to precipitation gathered by said well when precipitation occurs. - View Dependent Claims (15, 16, 17, 18, 19)
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20. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
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a block of electrically insulative material adapted to be embedded in the pathway and having a top surface exposed to precipitation; sensor means including at least three electrical conductors terminating substantially flush with the top surface of the block with the conductors having exposed portions that are exposed to the precipitation, a first distance separating the exposed portions of two of the electrical conductors and a second distance separating the exposed portions of a particular pair of the electrical conductors wherein the second distance is at least ten times the first distance; and means connected to the electrical conductors for measuring a first quantity related to electrical conductance between the two electrical conductors that are separated by the first distance and a second quantity related to electrical conductance between the particular pair of conductors that are separated by the second distance which is at least ten times the first distance, and for generating an output signal indicative of precipitation condition as a joint function of the first and second quantities. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
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a block of electrically insulative material adapted to be embedded in the pathway and having a top surface exposed to precipitation; sensor means including first, second and third electrical conductors embedded in the block and exposed to the precipitation wherein the top surface of said block is provided with a well for gathering precipitation around the first and second electrical conductors, the first and second conductors terminating in the well and the third conductor terminating outside of the well, the first and second conductors being separated by a first distance which is different from a second distance separating the second and third conductors; and electrical circuit means connected to said first, second and third electrical conductors for measuring a quantity related to conductance of the precipitation between said electrical conductors over the different first and second distances. - View Dependent Claims (32, 33, 34)
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35. Apparatus for detecting the presence and condition of precipitation on the surface of a pathway, comprising:
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a block of electrically insulative material adapted to be embedded in the pathway and exposed to precipitation;
sensor means including at least two electrical conductors affixed to the block and exposed to the precipitation, wherein corrosion forms on the conductors and endows them with a series capacitance in the presence of precipitation; andmeans for producing a warning when the series capacitance in the presence of precipitation is less than a predetermined capacitance. - View Dependent Claims (36, 37, 38, 39)
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40. In a method of making apparatus for detecting the presence and condition of precipitation on the surface of a pathway, the steps of:
- molding a block of electrically insulative material around a sensor embedded therein for sensing a physical property of the precipitation which property is also influenced by the depth of the precipitation; and
providing the top surface of the block with a well that is generally curved in outline above the sensor for gathering precipitation around the sensor thereby diminishing the influence of precipitation depth on the sensor. - View Dependent Claims (41)
- molding a block of electrically insulative material around a sensor embedded therein for sensing a physical property of the precipitation which property is also influenced by the depth of the precipitation; and
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42. In a method of making apparatus for detecting the presence and condition of precipitation on the surface of a pathway, the steps of:
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filling a mold with a curable material around a pair of electrically conductive pins and curing the material to produce a block of electrically insulative material having a top surface and adapted to be embedded in a pathway and exposed to precipitation; and grit-blasting the pins and their surrounding part of the top surface of the block to form a well for gathering precipitation entering said well, the electrically conductive pins thereby having portions thereof exposed to precipitation gathered in said well.
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43. A method for detecting the presence and condition of precipitation on the surface of a pathway, comprising the steps of:
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providing a block of electrically insulative material molded around at least three electrical conductors terminating substantially flush with a top surface of the block with the conductors having exposed portions that are exposed to precipitation, a first distance separating the exposed portions of two of the electrical conductors and a second distance separating the exposed portions of a particular pair of the electrical conductors wherein the second distance is at least ten times the first distance; electronically measuring a first quantity related to electrical conductance between the two electrical conductors that are separated by the first distance and measuring a second quantity related to electrical conductance between the particular pair of conductors that are separated by the second distance which is at least ten times the first distance; and generating an electrical output signal indicative of a condition of the precipitation as a joint function of the first and second quantities.
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44. In a method for detecting the presence and condition of precipitation on the surface of a pathway, the steps comprising:
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providing a block of electrically insulative material molded around a sensor including electrical conductors exposed to precipitation, wherein corrosion forms on the conductors and endows them with a series capacitance in the presence of precipitation; electronically measuring the series capacitance in the presence of precipitation; and producing an electrical signal indicating whether or not the series capacitance in the presence of precipitation is less than a predetermined capacitance indicative of excessive corrosion.
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45. In a method for detecting the presence and condition of precipitation on the surface of a pathway, the steps comprising:
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providing an electrical bridge with electrical conductors to sense the precipitation wherein the precipitation has a freezing point which is a function of an electrical conductance of the precipitation when the precipitation is wet and the electrical conductors have a series capacitance in series with the electrical conductance of the precipitation, the bridge including an adjustable impedance having an adjustable capacitance value and an adjustable resistance value, wherein the bridge produces a voltage representing a depth of null of the bridge which depends on the adjustable values; sensing the voltage from the bridge representing the depth of null of the bridge; adjusting the capacitance value and the resistance value of the impedance of the bridge to determine a particular capacitance value and a particular resistance value at which the null is deepest, the particular capacitance value then determined being related to the series capacitance and the particular resistance value thus determined being related to the conductance of the precipitation; producing an electrical output representative of a freezing point of the precipitation as a function of the particular resistance value at which the null is deepest provided the particular resistance value is less than or equal to a first predetermined amount indicative of wet precipitation; and further producing an electrical signal representing whether or not the particular capacitance value is abnormally low in value provided the particular resistance value is less than or equal to the first predetermined amount.
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Specification